Selective copper metallization by electrochemical contact displacement with amorphous silicon film

Abstract

In this study, we proposed a novel selective Cu metallization method by means of Si chemical mechanical polishing (CMP) and electrochemical Cu contact displacement from a-Si. The galvanic Cu deposition which involves the electrochemical redox reaction between cupric ions and silicon atoms could be carried out at room temperature in the HF aqueous solution. This selective Cu metallization method is promising for overcoming the obstacles in the current damascene process, such as the limitation of depositing comformally Cu seed into high aspect ratio trenches by physical vapor deposition for the following void-free Cu electroplating and nonplanarity issues after multistep CMP, such as Cu dishing and dielectric erosion. (C) 2001 The Electrochemical Society.